Axenically rearing the oriental fruit fly, Dacus dorsalis Hendel, through many continuous generations revealed that microbes were not essential for development. Absence of microbes did not affect the incubation period of the eggs, percent egg hatch, larval period, percent pupation, pupal period, adult emergence or the preovipositional period of the adults. However, axenic rearing had a highly significant effect on fecundity. Axenically reared flies laid significantly fewer eggs than xenically reared flies. Ovarian development was reduced in axenically reared females. Fecundity was not increased even when the axenically reared adults were fed food which increased fecundity in xenically reared adults. There were no differences in the fertility of the eggs laid by xenically or axenically reared flies.